Butadiene such as 1,3-butadiene is used as a raw material of styrene-butadiene rubber (SBR) or the like. In general, butadiene is purified from a C4 fraction which is produced as a by-product when ethylene is synthesized from petroleum.
However, recently, bioethanol synthesized from a biomass-derived raw material has attracted attention as an alternative raw material to petroleum. For example, PTL 1 discloses a method of producing butadiene from ethanol using a catalyst.
However, in the method of obtaining butadiene from ethanol using the catalyst as in PTL 1, the yield is not industrially sufficiently high. In addition, when butadiene is industrially produced, it is important to reduce a load on the global environment as much as possible.